Commitment and betrayal are the themes of this gracefully written novel by the author of Rhythms. Lisa Holden and Asha Woods have been best friends since the day they struck up a conversation as 12-year-old neighbors in an African-American enclave in Brooklyn. Like yin and yang, they have different personalities and dreams. Raised within a stable family, Lisa is now an English professor who always looks before she leaps; Asha, the product of a dysfunctional upbringing, is a worldly photographer who lives life spontaneously. When Lisa finds and weds her Prince Charming, architect Ross Davis, both women worry that the marriage will affect their relationship. Meanwhile, Ross, who is accustomed to taking care of the women in his life, feels emasculated by Lisa's control over their marriage. When Ross loses his job and Asha has a confrontation with her mother, they turn to each other for comfort and share one night together without considering the consequences. It doesn't take Lisa long to suspect the worst and to discover the truth. Similar betrayals have fueled innumerable plots, but Hill handles the emotional drama well, demonstrating that actions have long-lasting consequences. While the narrative should have broad appeal as a chronicle of human relationships, Hill uses good background detail to make the story more effective for her African-American core audience, introducing such issues as a white student's animosity toward a black professor, for example. Her thoughtful approach invests the love story with greater meaning. Agent, Pattie Steele-Perkins. Author tour. (Oct.)